R. Gonzalez, Secretary/Treasurer Jarigt Groth, President

Staff Report & Agenda Item Details

M. R. Gonzalez, Secretary/Treasurer Jarigt Groth, President Date Approved \\ \C \A 5 Page 6 of 6 DT _______ Minutes of 10-21-2025 10431 Morado Circle, Bldg. 5, Suite 300 + Austin, Texas 78759 + 512-617-3100 + FAX 817-735-7491 1.00 INTRODUCTION On July 2, 2025, the U.S. Fish and Wildlife Service (USFWS) released the results of its five-year review of the Pecos gambusia. In their report, the USFWS highlighted an ongoing regional challenge, “that there is conflict between the need for groundwater to support spring flows and the need for groundwater to supply irrigated agriculture.” The report further noted that “recognizing this conflict is essential to the species’ recovery because it highlights the other water users with whom the USFWS and other partners must collaborate in order to achieve recovery.” In response to the USFWS report and findings, Mr. Ty Edwards, General Manager of the Middle Pecos Groundwater Conservation District (MPGCD), requested that Freese and Nichols, Inc. (FNI) conduct a technical review of the Brackish Groundwater Production Zones (BGPZs) designated within the Rustler Aquifer. The objective of this review is to evaluate whether modifications to the current BGPZ boundaries are warranted based on amendment criteria, as well as ecological and regulatory considerations. 2.00 BACKGROUND BGPZs are defined as aquifers, or portions of aquifers, that have moderate to high availability and productivity of brackish groundwater. On May 26, 2015, the 84th Texas Legislature passed House Bill 30 (HB 30) to promote the development of brackish groundwater. The legislation directed the Texas Water Development Board (TWDB) to identify, map, and designate BGPZs within the state’s aquifers. HB 30 established a set of technical and regulatory criteria that an area must satisfy to qualify for BGPZ designation. These criteria are codified in Texas Water Code § 16.060(b)(5) and are summarized in Table 1. Additionally, HB 30 required the TWDB to study and consider designating BGPZs in four priority aquifers, that included the Rustler Aquifer, by December 1, 2016. These designations were intended to support the sustainable development of brackish groundwater in areas where freshwater or existing brackish supplies would be minimally impacted, in support of regional water supply planning efforts across Texas. TO: Ty Edwards, General Manager Middle Pecos Groundwater Conservation District FROM: Vince Clause, PG Alysa Sule, PG Freese and Nichols, Inc. SUBJECT: Rustler Brackish Groundwater Production Zone -- Request for Amendments PROJECT: MPG24752 – FY26 Hydrogeological Consulting Services DATE: October 17, 2025 Attachment: Attachment A – Supporting Well Documentation www.freese.com TECHNICAL MEMORANDUM Attachment A Ruslter Auifer BGPZ Tech 2 Table 1. Summary of criteria used to designate brackish groundwater production zones. Plain-Language Summary of Criteria Texas Water Code (§16.060(b)(5)) Language Adequate Brackish Groundwater Availability – The area must contain moderate to high quantities of brackish groundwater that can be developed. “identification and designation of local or regional brackish groundwater production zones in areas of the state with moderate to high availability and productivity of brackish groundwater that can be used to reduce the use of fresh groundwater” Hydrogeologic Barriers from Fresh Groundwater – Brackish and fresh groundwater zones must be separated by hydrogeologic barriers sufficient to prevent significant impacts to water availability or quality. “separated by hydrogeologic barriers sufficient to prevent significant impacts to water availability or water quality in any area of the same or other aquifers, subdivisions of aquifers, or geologic strata that have an average total dissolved solids level of 1,000 milligrams per liter or less at the time of designation of the zones” E